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Alpha-Blocker (1/6): General Side Effects and Contraindications

Review Literatur: (Chapple, 2004).

Alpha-Blocker: General Mechanism of Action

Postsynaptic alpha₁-blockade leads to:

Smooth muscle relaxation of the prostate, bladder neck and the urethra. Alpha-blocker are drugs of first choice to improve micturition in patients with benign prostatic hyperplasia (BPH).
Smooth muscle relaxation of the bladder trigonum and distal ureters. Off-label treatment with alpha-blockers leads to a faster spontaneous passage of distal ureteral stones.
Following sub-types of alpha₁-receptors are known: A, B, D and L. Type alpha_1A appears to be most important in the prostate for the inhibition of subvesical obstruction.
Additional improvement of LUTS by the blockade of alpha₁-receptors on the spinal level, in the urinary bladder and on afferent nerves.
Arterial and venous vasodilation with reduction of arterial blood pressure. Alpha-blocker are drugs of second choice to treat arterial hypertension.

Side Effects of Alpha-Blocker

Overall rate of side effects is between 10–30%, selective alpha_1A-blocker have a reduced cardiovascular side effect rate.
Initial hypotension, orthostatic collapse, reflex tachycardia, usually transient.
Increased risk (HR 1,2) of cardiac failure (Lusty et al, 2021).
Stuffy nose
Retrograde ejaculation
Dizziness, weakness

Contraindications of Alpha-Blocker

Urological Contraindications:

Conservative treatment of BPH is not indicated, if surgical treatment is imperative: chronic urinary retention with renal failure, recurrent hematuria due to prostatic enlargement, recurrent infections or bladder stones.

Cardiac Contraindications:

Hypotension, mechanical heart failure (valvular, pulmonary embolism, pericarditis), congestive heart failure.

Other contraindications:

Severe liver insufficiency. Alpha-blocker should be paused perioperatively for cataract surgery to prevent an intraoperative floppy iris syndrome.

Drug interactions

Do not combine two alpha-blocker for better treatment effect.

Pharmacology

Index

Terazosin

Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

References

Chapple 2004 CHAPPLE, C. R.:: Pharmacological therapy of benign prostatic hyperplasia/lower urinary tract symptoms: an overview for the practising clinician.
In: BJU Int
94 (2004), Nr. 5, S. 738–44

Deutsche Version: Alpha-Blocker